The constraints and their derivatives are formed by opf_consfcn.m. -- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645
On May 19, 2013, at 9:06 AM, Aftognosia Aftognosia <[email protected]> wrote: > Dear Dr Zimmerman, > > I would like to ask you, where is it possible to find the source code of the > matpower ACOPF equations? > SInce you already mentioned that it is open to everyone! > > Thank you > > From: Ray Zimmerman <[email protected]> > To: MATPOWER discussion forum <[email protected]> > Sent: Tuesday, May 14, 2013 7:32 PM > Subject: Re: branch modeling > > Yes. > > On May 14, 2013, at 12:55 AM, Petre Razusi <[email protected]> wrote: > >> Thank you Prof. Zimmerman. Your explanations helped me. However, I still >> have another thing that is a little bit unclear. >> I have some transformer parameters (in Ohms and Siemes) calculated using the >> "to" side voltage. How do I convert them to p.u.? Do I use the same Zbase >> that you suggested? >> >> Thank you for your help! >> >> Petre >> >> >> 2013/5/13 Ray Zimmerman <[email protected]> >> Since the branch impedances are on the "to" side of the branch, you are >> correct that you would use the voltage base from the "to" bus. >> >> The formula isn't really a MATPOWER question, so you should be able to find >> the answer in a good power systems textbook, however it is very >> straightforward to derive yourself. Essentially we want to find the >> impedance base (Zbase) in terms of the power and voltage bases (Sbase and >> Vbase). >> >> Start with some definitions ... >> >> (1) V = Vpu * Vbase >> (2) S = Spu * Sbase >> (3) Z = Zpu * Zbase >> >> Then some simple relationships ... >> >> (4) V = I * Z >> (5) S = V * conj(I) >> >> Solving (4) for I and substituting in (5), then solving for Z, gives ... >> >> (6) Z = |V|^2 / conj(S) >> >> And we know the p.u. quantities have the same relationships … >> >> (7) Zpu = |Vpu|^2 / conj(Spu) >> >> Substituting (1)-(3) and then (7) into (6) and rearranging, gives … >> >> Zbase = Vbase^2 / Sable >> >> Hope this helps, >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> >> On May 13, 2013, at 3:44 AM, Petre Razusi <[email protected]> wrote: >> >> > Dear all, >> > >> > I have some things I don't quite understand regarding the modeling of >> > branches and the pu system. >> > If I'm not wrong, to transform the R,X and B parameters to pu one needs a >> > base impedance. Since the model used for the branch is a complex one, >> > dealing with both transformers and lines, I presume that this impedance is >> > calculated using the "to" bus voltage. Am I right? And if so, could you >> > tell me what is the formula used to compute the base impedance? >> > >> > Thanks, >> > >> > Petre >> >> >> >> >> >> >> > > >
